support passing a Readable stream as the stub for S3.GetObject

[jstewmon]

• swapped tape with tap to get afterEach, so that the sandbox can be
  predictably restored after each test.
  • removed all restore calls that do not test restore feature
• skipped the test about a stub being returned because that behavior
  only applies when the service constructor has already been called when
  mock is called. the test previously passed due to side effects of
  unrestored sandbox.

fixes #142

[nelsonic]

@jstewmon this PR looks promising! please link to an issue https://github.com/dwyl/aws-sdk-mock/issues for context. thanks! 👍

[codecov]

Codecov Report

Merging #144 into master will increase coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #144      +/-   ##
==========================================
+ Coverage   99.06%   99.08%   +0.01%     
==========================================
  Files           1        1              
  Lines         107      109       +2     
==========================================
+ Hits          106      108       +2     
  Misses          1        1

Impacted Files	Coverage Δ
index.js	99.08% <100%> (+0.01%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 8b101d2...26f3975. Read the comment docs.

[stephanschubert]

LGTM?

[nelsonic]

@Jazen do you "second" the need for this issue: #142 ? (thanks!)

[stephanschubert]

@nelsonic Yes, because the AWS SDK docs say:

All requests made through the SDK are asynchronous and use a callback interface. Each service method that kicks off a request returns an AWS.Request object that you can use to register callbacks.

Example:

var out = fs.createWriteStream('/path/to/outfile.jpg');
s3.service.getObject(params).createReadStream().pipe(out);

[nelsonic]

@jstewmon thank you for taking the time to prepare this Pull Request
with improvements to both tests & docs! 🎉

@Jazen thanks for confirming. 👍

[nelsonic]

@jstewmon aws-sdk-mock@4.1.0 is now on NPM.
thanks again! 🥇

[lucaslago]

awesome, thank you!